killswtch's Home Automation and Media Projects
This is the story of my attempts at integrating various technologies into a 3-bed semi, constructing as much of the hardware and electronics as possible myself.
Wednesday 18 June 2008, 8:45 PM
Last of the amplifiers
There are 4 audio zones in the house, each requiring it’s own amplifier and pair of speakers. I’ve just purchased the last of the amplifiers, which completes the selection of hardware that’s necessary within the cabinet. I took the opportunity to rearrange the order of things in the rack a little to tidy things up.
Wednesday 18 June 2008, 8:44 PM
Switch consolidation
We recently had our latest electricity bill in, and it was pretty huge. To try to reduce the next bill, reduce the heat output of the cabinet and speed up the network I decided to combine 5 switches into one.
Before now all devices in the house have been connected to one of 3 switches: a 5 port gigabit switch (4 usable ports, 1 for uplink), a 24 port managed 10/100 switch, and a 4 port managed gigabit switch (3 usable ports, 1 for uplink. These switches used a combined 51 watts, and are on continuously, although lately I’ve switched the 4 port gigabit switch off to reduce the noise levels in the cabinet.
I have now replaced these 3 switches with a single 24 port unmanaged gigabit switch. It was a 2nd hand purchase from eBay, and had 2 faulty fans. I’ve replaced one of the fans and left the other disconnected with no problems so far. This switch uses about 17 watts of power.
In addition to consuming 34 watts less, I’ve also freed up 1u of space. With all the amplifiers, computers, networking equipment etc. space is starting to become a premium and the weight of the rack is becoming a concern.
Wednesday 18 June 2008, 8:42 PM
Measuring power consumption
A recent electricity bill has prompted me to investigate how much power is being used by each device in and around the cabinet in the hope of figuring out what can be replaced to reduce running costs. I’ve had a power monitor from Maplin for a while, but most of the time it’s been monitoring total power consumption of the rack.
Power
* UPS: ~50W non-charging
Networking
* 24 port 10/100 switch: 25W
* 4 port 10/100/1000 switch: 18W
* 5 port 10/100/1000 switch: 8W
* Router: 3W
* Modem: 3W
Computers
* Boron (fileserver): 150-190W
* Aluminium (desktop): 250-295W
* Barium (HTPC): 66-85W
The audio system components haven’t been measured yet because at the moment they aren’t ready to drive a load and measuring the idle consumption wouldn’t be very meaningful. The amplifiers will be switched off when not in use and won’t be used that much compared to the items listed above.
Based on the data above, I have replaced the 3 switches with 1 switch. I have been investigating replacing boron with a collection of NAS devices for storage and a low-power ITX-based machine for services such as DHCP and DNS. However this is currently quite an expensive option.
Aluminium is a gaming-spec PC so will always consume quite a bit of power, however I’ve got some software under development which should mean that I won’t need to keep it on to download the occaisional torrent - that job could be offloaded to boron or my hosted server.
Barium is only on when I want to watch a DVD, a video or recorded TV from MythTV. It was specced to be quiet and consume as little power as possible with a Core 2 Duo CPU, 1GB DDR2, a passively cooled HDCP-capable VGA/DVI graphics card and a quiet PSU.
I’m going to continue to look at reducing consumption not just in the rack but around the rest of the house.
Wednesday 18 June 2008, 8:40 PM
Serial port problem solved
Thanks to the chip manufacturer of the cheap serial port card, I’ve managed to get some extra serial ports working. If you can’t figure out how to get additional serial ports working, I recommend this guide [ZIP, 792KB] available from the Moschip driver download page. It should be valid for most models of serial cards, and explains how to add more than the standard 4 ports that most linux installs have.
Now that this problem is out of the way I can continue with writing the remote control software for the audio system.
Wednesday 18 June 2008, 8:38 PM
Serial port problem part-way resolved
Having put the 4 port serial card back into boron, the onboard port now works again, so I’ll probably continue with developing the software. The expansion card still doesn’t work though, so I’ve ordered a cheap 2-port card from eBay in the hope that a different card will work.
Before reinstalling the card I upgraded Ubuntu to see if that would help (it didn’t) which brought its own scary moment of the 1TB RAID volume being dead. That too is solved now - the drive letter assignments had changed.
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